That could be. Also there is a config file with the fixed ip on normal boot when in failsafe mode (that could be reason of not able to access it in browser mode as the ip could become an old one, was the case for me).

this is where you set ip in openwrt if you entered it wrong:
vi /etc/config/network
config interface 'lan'
        option ifname 'eth0'
        option type 'bridge'
        option proto 'static'
        option ipaddr '192.168.0.100'
        option netmask '255.255.255.0'
        option gateway '192.168.0.1'
        option broadcast ''
        option dns ''